Prepare the LIDS sealing

Sealing LIDS is an important operation that consist in blocking a lot of important system calls, ioctls, etc. after the initialisation of the system. For exemple, you must forbid module loading/unloading to have a secured system. But you may want to load some modules you cannot include in the kernel (kernel too big, or binary-only modules). You may also prevent anybody from mounting/unmounting devices, but you must mount some devices at startup.